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Von Duprin 101

Power Supplies


Power supplies are essential for maintaining electric strike door integrity and functionality, providing regulated power to your comprehensive access control system.   


Looking for more information? Connect with an Allegion team member for help.


A power supply's main role is to transform the electric current to the right voltage and frequency to power devices like electric strikes, electric latch retraction, exit devices and electrified locks, ensuring the operational reliability of your security system. 

Electricity travels within a circuit to allow various operations. Every circuit has four basic elements:

Load - In architectural hardware, the load refers to the product using electricity to operate.  Examples include electrified locks, electric strikes, and electric latch retraction exit devices

Power Source - Power sources supply the voltage necessary for operation. They must be able to handle the current flow required by the electrified hardware 

Conductor - Conductors carry the flow of electricity within circuits and are commonly a cable or wire

Switch - Switches open and close to control the flow of electrical current

Want to learn more? Dive into our Intro to Door Hardware: Electricity Basics video

  • Power supplies adapt high voltage AC power into the low voltage DC outputs required by most access control devices, like electric strikes and electric mortise locks
  • Begin by checking the input voltage to ensure that it is compatible with your buildings source AC power
  • Many power supplies feature a universal 120-240 VAC input
  • All devices fed from a power supply must accept the same output voltage – typically 12 VDC or 24 VDC
  • To calculate the total load, add the peak current draw of all devices in the system to determine the required amperage of the supply
  • In general, the total peak load of the devices should be no more than 80% - 90% of the power supply amperage


To learn more, please review the Guide to Selecting a Power Supply

  • A linear or switching power supply is typically specified for access control solutions that use electrified and electronic hardware devices 
  • No matter the type of power supply, it must be designed to handle the load and in-rush requirements of the opening
  • Regulated power supplies provide consistent, clean and filtered output and are recommended for use in opening applications
  • Certain devices, including Von Duprin EL and Falcon EL exits, pull a significant current to retract or unlock the device and then drop to a lower holding current. As such, devices like these need a power supply specifically designed for high in-rush applications 

To learn more about how to choose the right power supply for a project, please review the Guide to Selecting a Power Supply.

  • Input voltage range: 120/240 VAC, 50/60 HZ, universal input
  • Output voltage: 12 or 24 VDC; field configurable with jumper
  • Enclosure: # of cutouts for running wires, keyed locking option
  • DC output protection: Overload protection - current limited foldback circuit
  • LED status indicators: AC input (visible on outside of closure), DC output
  • Fire alarm board: optional; configure as switched (power cut) or unswitched (power continues) when signal is provided
  • Battery back-up board or kit:  optional; enables up to four hours of backup power at the same output voltage as the power supply
  • Option boards: optional; enables a wide range of applications with logic and sequencing based on the operational description of the opening

Features and options will vary by model; please see the available products section for specific details.


  • Gauge and wire run are important to the performance of an electrified hardware circuit
  • The wire run refers to the distance from the power source to the product. The longer the run the more resistance there will be
  • Resistance turns current into heat. Known as voltage drop, this process makes less overall electrical current available to allow operation
  • If a power source is very far away from the electrified locking device, a larger gauge wire will be necessary to ensure electric door strikes and other electrified hardware receive the power they need for uninterrupted operation

To learn more about wire gauge and run, please review the Guide to Selecting a Power Supply.

Model codes are frequently used as the basis for many state building codes, but specific locations may adopt previous editions or add amendments as they see fit. Therefore, it is encouraged to confirm a jurisdiction’s codes prior to the specification of all components for emergency exit doors and fire exit hardware, including codes based on:

Authorities Having Juristriction (AHJ) have the final say at the local level. That said, we recommend consulting with your Allegion Code Expert (ACE) to confirm specifics regarding power supplies as a low voltage license may be required in some locations.

Click here to reach the Allegion Code Expert (ACE) in your state.

For more information on building codes, please visit

Power supplies fit a variety of applications; powering openings with the following devices:

  • Access control readers 
  • Automatic operators
  • Electrified exit devices
  • Electrified locks
  • Electrified strikes
  • Electrified trim
  • Electromagnetic locks
  • Electronic locks and accessories that are hardwired

It is encouraged to contact an Allegion Code Expert or AHJ to confirm the codes relevant to the configuration of any and all power supplies.

When choosing a power supply configuration, it is important to consider the following:

1. The number and types of devices that will be connected to the power supply 

  •     Devices can include: electric strikes, electromagnetic locks, electrified mechanical locks, exit devices, automatic operators or accessories such as pushbuttons 
  •     Each type of device has specific current demands. A power supply must be able to provide enough electricity to cover the peak draws of all connected devices—including high in-rush exit devices that pull a large current to activate
  •     All devices connected to a common power supply must accept the same output voltage - typically 12 VDC or 24 VDC
  •     If a device has an in-rush current, how long the in-rush current lasts should also be determined

2. Peak current draw of all connected devices. Calculating this and comparing it to a power supply’s amperage ensures all systems will function properly. The Guide to Selecting a Power Supply provides specific details

  •     PS902 - up to 2 amps
  •     PS904 - up to 4 amps
  •     PS906 - up to 6 amps
  •     PS914 - up to 4 amps high in-rush

3. The complete operational description of the opening

  •      Identify if the opening is fire rated or has special requirements such as re-entry upon fire alarm; if so a fire alarm board is required
  •      Determine if it requires hardware for fail-safe, fail-secure or both conditions upon loss of power or fire alarm
  •      How many doors?  
  •      Is logic or sequencing required?  
  •      Always consult your local AHJ for requirements of the opening if it is unclear

3. Types of option boards; the Guide to Selecting a Power Supply offers insights on how to choose systems and how to accommodate the boards, including distinguishing between boards

  •     900-FA: Emergency interface relay integrates with automatic fire alarms to cut power during an emergency
  •     900-4R: 4 independently controlled relays to power multiple devices
  •     900-2RS: 2 relay EL panic device control board ensuring a time delay between the firing of outputs
  •     900-4RL: 4 relay board with integrated logic that controls security interlocks, auto operators and time delays
  •     900-8F: 8 individually fuse-protected outputs, to power multiple devices and provide another layer of protection and flexibility
  •     900-8P: 8 positive thermal coefficient (PTC) protected outputs

 4. If access control is still required in the event of a power outage; please refer to the Guide to Selecting a Power Supply to learn more

  •     900-BBK: Battery backup kit (includes battery backup board and two 7A/hr. batteries) and provides up to four hours of backup power when cycled every 5 minutes at full load

Visit our Power Supplies page to review available options.

Please contact us if you need additional information or assistance.

Specific product pages can provide more information on fire alarm boards, option boards and battery backup boards and kits.

Allegion Customer Service (Sales Support) or Technical Support (Product Support) can provide more information or assistance. These support services can be contacted by phone or email.  

To contact by phone: call 877.671.7011

PRESS Option 1 for Customer Service then select your specific product category:

  • Mechanical Locks & Keying Systems by Schlage, Falcon or Dexter, PRESS 1
  • Electronic Locks, System Components, Biometrics, Readers or Credentials, PRESS 2

PRESS Option 2 for Technical Support then select your specific product category:

  • Mechanical Locks & Keying Systems by Schlage, Falcon or Dexter, PRESS 1
  • Electronic Locking Products AD, CO, NDE, LE, Control, Express, Engage, Multi-Family Solutions, ISONAS Hardware or Pure Access Software, PRESS 2
  • For AD, CO, PIM, Express, BE367/FE210 and all legacy related locks like CM and King Cobra, PRESS 1
  • For ENGAGE related products including NDE, LE, Control, CTE and Gateway, PRESS 2
  • For ISONAS Hardware and Pure Access Software, PRESS 3
  • Readers and Credentials, Biometrics or System Components such as Maglocks or key switches by Schlage or Locknetics, PRESS 6

PRESS Option 3 to reach your local sales office, you will be directed based upon the area code from which you are calling


Sales Support (Customer Service for all Product Categories and Regions) - 

Technical Product Support:

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As part of Allegion’s family of pioneering brands, Von Duprin benefits from the strength, efficiencies, resources, and integration from a global power. In turn, we pass those advantages on to you.

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